1. Field of the Invention
The invention relates to toilet flushing systems which conserve water by providing different amounts of water flushing potential depending upon the type of waste to be removed from the toilet.
2. Description of the Prior Art
Toilet flushing systems consume a large amount of water every day. Most such systems use the same volume of water regardless of the type of waste to be removed from the toilet, resulting in needless water consumption.
U.S. Pat. No. 4,406,024 discloses a flushing actuator which opens a single flush valve for varying lengths of time, releasing different amounts of water to the toilet depending on the waste removal requirement. However, the different flushing levels are coupled in a manner which can often result in selection of the incorrect flushing level. For example, flush volume is selected by depressing the handle of the controller for a short time for a small volume or a long time for a large volume. Since the user must guess the approximate length of time to depress the handle, either too much or not enough flush water is often used for a given waste removal requirement.
Dual valve flushing systems are disclosed in U.S. Pat. Nos. 2,864,095, 3,913,149, 3,909,856, 4,042,982 and 4,122,564. Although these dual level flushing systems may avoid the problems associated with the above described device, they require special parts rather than standard plumbing items. In addition, absent other modifications to the prior art toilet flushing systems, the lesser head pressure associated with a smaller flush volume may not adequately remove even lesser quantities or less solid types of waste.
For example, the dual level systems include two different height conduits which discharge water to the toilet. The tall conduit is usually about twice the height of the short conduit; consequently, the tall conduit, having only about half the water head pressure or flushing force of the short conduit can convey only half as much water to the toilet. The available flushing force of water in the tall conduit is diminished by the flow discontinuities induced by a sharp bend in the conduit from vertical to nearly horizontal near the discharge point of the toilet in combination with the further force dissipating change in the direction at the discharge outlet.